Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
  • C01B15/01—Hydrogen peroxide
  • C01B15/013—Separation; Purification; Concentration
  • C01B15/017—Anhydrous hydrogen peroxide; Anhydrous solutions or gaseous mixtures containing hydrogen peroxide

Definitions

• the invention relates to a process for the core hydroxylation of phenol or phenol derivatives using the compound to be hydroxylated as a solvent for hydrogen peroxide.
• Non-aqueous solutions of hydrogen peroxide in a wide variety of organic solvents are known to be used in many reactions, e.g. Oxidations, epoxidations or used in nuclear hydroxylations of phenols. Since the presence of water has a disturbing effect on the reactions mentioned, attempts have been made to obtain organic solutions of hydrogen peroxide which are as low in water as possible, see FIG. Org. Reactions 7: 395 (1953); DE-C 2038319; 2038320; DE-B 2410742; 2462957, 2462990.
• EP-A 0122374 (published on October 24, 1984 and belonging to the state of the art under Article 54 (3) EPC) is directed to a process for the nuclear hydroxylation of substituted phenols or phenol ethers with a practically anhydrous solution of hydrogen peroxide in an organic solvent in the presence of sulfur dioxide as a catalyst.
• This process also first requires the preparation of a practically anhydrous solution of hydrogen peroxide in an organic solvent, alkyl or cycloalkyl esters of saturated aliphatic carboxylic acids being preferably used, and finally the removal of this solvent during the workup of the reaction mixture.
• alkyl or cycloalkyl esters of saturated aliphatic carboxylic acids being preferably used
• the object of the invention is thus a simplified process for the nuclear hydroxylation of phenol or phenol derivatives with a practically anhydrous solution of hydrogen peroxide in organic solvent in the presence of a catalyst which allows the compound to be hydroxylated itself to be used as a solvent for hydrogen peroxide and the necessary solutions of hydrogen peroxide in phenol or phenol derivatives in a single process step and without decomposition of hydrogen peroxide and without danger or formation of explosive vapor mixtures practically water-free.
• Phenol derivatives are understood to mean alkyl derivatives, such as cresols, ethyl or butylphenols, arylphenols, such as 4-hydroxybiphenyl, alkoxyphenols, such as anisole and its aryl or halogen derivatives, phenyl ether, phenyl isopropyl ether or p-cresol methyl ether.
• the solvents should be selected so that a lot of aqueous hydrogen peroxide dissolves in such a way that the existing water can be towed away. This is understood by the expression "sufficiently homogeneous”. It can be determined by a preliminary test.
• the distillation itself is first carried out at atmospheric pressure to remove the water as an azeotrope and to remove the bulk of the solvent; the remaining solvent can be removed at a low, not critical negative pressure, e.g. with phenol up to 100 mbar.
• the distillation can initially also be carried out with a slight excess pressure, e.g. up to 3 bar.
• Preferred solvents are halogenated, aliphatic, low-boiling hydrocarbons, such as dichloromethane, trichloromethane, fluorotrichloromethane, dichlorodifluoromethane, preferably dichloromethane.
• Low-boiling ethers such as diethyl ether, methyl isopropyl ether and methyl tert-butyl ether, are also suitable.
• Hydrogen peroxide is used in aqueous solutions of 3 to 90% by weight of hydrogen peroxide, preferably 30-85% by weight.
• Weaker solutions than 3% by weight are technically uninteresting because of the very large amount of water to be removed as an azeotrope. Solutions with a higher concentration than 90% by weight can give rise to the formation of sensitive mixtures.
• the compound to be hydroxylated is itself used as a solvent for hydrogen peroxide.
• the core hydroxylation reaction takes place at temperatures from 20 to 200 ° C.
• the preferred temperatures are from 120 to 180 ° C when using sulfur dioxide as a catalyst, and between 100 and 170 ° C for selenium dioxide.
• the pressure range to be used is not critical; in general one will work at normal pressure, although negative or positive pressure are possible, e.g. Overpressures up to 2 bar.
• Sulfur dioxide can be used both in gaseous form and in dissolved form.
• the hydrogen peroxide solution i.e. Phenol or phenol derivative
• alkyl or cycloalkyl esters of saturated, aliphatic carboxylic acids which have a total carbon number of 4-8, in question, especially n- and i-propyl acetate, ethyl acetate.
• Methylene chloride can also be used as a solvent here.
• dialkyl ethers or esters of phosphoric or phosphonic acid can also be used.
• the concentration of these sulfur dioxide solutions is generally 0.5 to 50% by weight, preferably 1 to 10% by weight.
• the sulfur dioxide catalyst is used in very small amounts, ie in amounts of 0.0001 to 0.1 mol, preferably 0.0005 to 0.01 mol, based on 1 mol of hydrogen peroxide. This is extremely little compared to the amounts of strong mineral acids used to date.
• the ratio of pyrocatechol to hydroquinone or that of two possible ortho substitution products can be influenced by using selenium dioxide as a catalyst.
• the ratio of pyrocatechol to hydroquinone can be varied between 5: 1 and 1: 1, although the theoretical ratio is 2: 1.
• the para position to the OH group is occupied by a substituent, for example a methyl group
• the second hydroxyl group can occur ortho to the first OH group and also to the CH 3 group.
• the resulting products are then 4-position substituted catechols or resorcins.
• Selenium dioxide is used in solid form, preferably as a powder, in amounts of 0.0001 to 5 mol, preferably 0.0005 to 0.2 mol, based on 1 mol of hydrogen peroxide. It can also be used in dissolved form, for example as a solution in phenol or the phenol derivative. The concentration of such a solution is 0.1 to 10% by weight.
• the solutions of hydrogen peroxide to be used in phenol or phenol derivatives can be varied during production such that the molar ratio of phenol or phenol derivative to hydrogen peroxide is 5 to 20: 1, preferably 5 to 15: 1.
• the reaction times are short both when using sulfur dioxide and selenium dioxide. You over with a turnover of 99% practically do not last for 30 minutes. If sulfur dioxide is used as a catalyst, the reaction is practically complete after only 10 minutes.
• the core hydroxylation of phenol or phenol derivatives which is carried out with the catalysts sulfur dioxide or selenium dioxide, can be greatly simplified by using the solutions of hydrogen peroxide in the compounds to be reacted.

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• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
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• 1983
  • 1983-09-27 DE DE19833334854 patent/DE3334854A1/de active Granted
• 1984
  • 1984-09-06 EP EP84110595A patent/EP0139194B1/de not_active Expired
  • 1984-09-06 AT AT84110595T patent/ATE32869T1/de not_active IP Right Cessation
  • 1984-09-06 DE DE8484110595T patent/DE3469718D1/de not_active Expired
  • 1984-09-07 US US06/648,137 patent/US4686010A/en not_active Expired - Fee Related
  • 1984-09-26 CA CA000464083A patent/CA1198127A/en not_active Expired
  • 1984-09-26 ES ES536241A patent/ES8505617A1/es not_active Expired
  • 1984-09-27 JP JP59200707A patent/JPS6090803A/ja active Pending
• 1987
  • 1987-08-04 US US07/081,366 patent/US4760199A/en not_active Expired - Fee Related

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